Unit 7 Vocabulary: Genetics
Genetics - The field of science that looks at how traits are passed down from one
generation to another, through the genes.
Trait - characteristic that is inherited; can be either dominant or recessive
Allele - One of a number of different forms of a gene. Each person inherits two
alleles for each gene, one allele from each parent.
Genotype - The set of genes possessed by an individual organism for a specific
trait. Two letters are used to represent the genotype, one for each allele, for
example Bb.
Phenotype - The physical appearance of an organism that is determined by the
genotype, for example blue eyes.
Dominant - An allele with a phenotype that is expressed (or shown) whether the
allele is heterozygous or homozygous. It is represented by a capital letter.
Recessive - The phenotype that only shows up in the offspring if the dominant
allele is not inherited. It is represented by a lower case letter.
Chromosome - Part of a cell that is made of DNA and contains genetic
information. Except for sperm and eggs, all human cells contain 46 chromosomes.
Gene - The unit of heredity passed from parent to offspring. Genes are pieces of
DNA, and most genes contain the information for making a specific protein.
Gene Expression - The process by which a gene's information is converted into
the structures and functions of a cell. Not every gene is expressed in every cell.
Heredity - The handing down of certain traits from parents to their offspring. The
process of heredity occurs through the genes.
Heterozygous – Having both the dominant and recessive members of a pair of
alleles. (Aa)
Homozygous - Having two identical alleles of a particular gene (ex.: GG or tt).
DNA - The material inside the nucleus of cells that carries genetic information.
The scientific name for DNA is deoxyribonucleic acid.
Base Pair Rule - The nitrogenous base adenine always pairs with thymine (A-T)
and guanine always pairs with cytosine (G-C). We say that A and T are
complimentary and G and C are complimentary.
Replication - The process of duplicating the DNA to make two identical copies,
one of which will be passed along to each daughter cell when the cell divides.
Gel Electrophoresis - A technique used to separate molecules based on size. The
gel allows shorter lengths of DNA to travel more quickly than longer pieces of
DNA, creating a DNA fingerprint.
Restriction Enzymes - Enzymes that recognize specific regions of a long DNA
molecule and cut it at those points.
RNA - A single-stranded nucleic acid (similar to the double-stranded nucleic acid
DNA) involved in protein synthesis. There are three types messenger RNA,
transfer RNA and ribosomal RNA
Codon - The sequence of three nucleotide bases in mRNA that codes for a specific
amino acid.
Transcription - The process by which DNA passes genetic information to RNA.
Transcription is the first step in producing proteins.
Translation - The process of protein synthesis from a mRNA template, occurring
at the ribosome.
Mutation - A change or alteration in a gene so that it does not work in the normal
way. There are three types:
Insertion – The type of mutation that occurs when an extra base is added to
the DNA strand.
Deletion – The type of mutation that occurs when a base is removed from
the DNA strand.
Substitution – The type of mutation that occurs when one base is
substituted for a different base in the DNA strand.